Piston-head packing for rock-drills



(No Model.)

L. S WOODBURY.

@ISTON HEAD PACKING FOR ROGK DRILLS. No. 319,538. Patented June 9, 1885.

N P EH5. PlwQo-Lllhogmpher. Wuhingfon. D. C.

V UNITED. STATES:

PATENT f OFFI E.

LEANDER s. WOODBURY, or CALUMET, MICHIGAN.

PISTON-HEAD PACKING FOR IROCK-DRQILLSVL SPECIPICATIO'Nforming part of Letters Patent No. 319,538, dated June 9, 1885.

Application filed J anuary 8, 1885. (No model.) i I 7 To all whom it may concern: Be it known that I, LEANDER S. W001)- BURY, a citizen of the United States, residing at Calumet, in the county of Houghton and State of Michigan, have invented a new and useful Improvement in Piston-Head Packing for Bock-Drills, of which the following is a specification.

ing which is held out against the cylinder with a spring or springs set in behind it, and is especially intended for use in rock-drills where air-pressure is the motive power, though it may be used with other pressures and in other kindred machines.

My invention has the following objects: first, to secure absolute tightness without undue friction, the especial necessity for which will be fully set forth; second, to' avoid the derangement common to the packing usually used in rock-drill piston-heads; third,to enable the user of the drill to repair or replace the packing, thus avoiding the expense of shop repairs and the delays incident thereto. These objects are accomplished in the devices illustrated in the accompanying drawings, in which- Figure 1 is a central longitudinal section of a portion of the cylinder, cylinder-head, and piston-head and packing, the rod being shown in elevation. Fig. 2 is a plan of the packing and spring. Fig. 3 is a side elevation of one section of the packing, for the purpose of showing the method of splitting the same.

Similar letters refer to similar parts throughout the views, in which- A is a portion of the cylinder. B is a portion of the lower cylinder-head. G is the piston-rod. D is the piston-head. P is the pis 4o ton-head packing, and S is the spring under the packing.

Having thus described the parts, I will proceed to describe their operation, their necessity, and method of accomplishing the objects 5 specified above, referring to these objects in their order.

First. In rock-drills and kindred machines the limit of the stroke at the lower end is governed by'the drill striking the rock,and at the upper end by an air-cushion between the piston-head and cylinder-head. In the latter My invention relates to that class of pack-- rod 0 there is no escape for the air remaining .head, and on the lower end, when from any causesuch as improper feeding or a broken 5 5 drill the latter would not prevent the pis-- ton-head. from striking the cylinder-head,

the air-cushion is also relied upon to prevent Now',,with a proper. packing around the in the cylinder at either end, unless it be by the-pistoirhead packing, and as in the cases used in steam and air cylinders gencrally,being asimple ring cutintwo places. Now,'itisawe1lknown fact. that most all cylinders in which a metallic packing is used are worn tapering,being thelargest at the ends, and they are often also worn out of round or become out and scored by the packing being improperly lubricated; but these derangements are especially pecu= liar to the rock-drill, first, by reason of the lateral strain that often comes upon the piston and piston-head, and, second, because of the dust and grit peculiar to mining operations being carried into the cylinder in the air, and, third, because when air is used it has no lubricating qualities, as is the case with saturated steam. Now, a metallic packing suitable to withstand the shock and jar incident to this class of machines will not accommodate itself 85 to the inequalities above specified, and a leakage takes place, especially at the ends, where the most perfect confinement of the air is required. To obviate these difficulties,Imake use of fibrous rings P, of a compact nature-as leather, rawhide, compressed or vulcanized fiber, leather and rawhide being considered preferable to the others. These rings are cut in one place, as shown from at to 00, Fig. 3,and are so placed in the piston-head as to break the joints, as shown in Fig. 2. The rings being thus cut readily yield to the pressure of the spring S, which keeps them out against the cylinder. Should there be any inequali- KOO nd, With thi p ng t e class f dera gem nts referred t will, not occur, (1.1,) b cause the packing will wear in preference to the cylinder, and (b) this packing, by reason of its nature, will retain any lubricant that may be applied to it, and the cylinder thus becomes more perfectly lubricated. There is one other class of derangements that this packing obviates. The metallic packing has to be made, as before intimated, suitable to withstand the shock and jar incident to this class of machines, and its inertia is from six to eight times that of the fibrous packing P. 'As the metal ring has to be fitted in the groove of the piston-head so that it will move freely, every time the drill strikes the rock the packing makes a blow upon the side of the groove, which very soon becomes worn thereby, and, constantly increasing, occasions a leak around behind the ring, and the constant hammering of the ring as this wearincreases frequently breaks it, when the drill becomes useless until repairs are made. The rings P being-so much lighter and of a yielding-nature, no such difficulty arises from their use; but

Third. When from any cause the rings P need to be repaired or replaced, the user of the drill, by loosening the lower head, can draw down the piston-head and insert a new setwith little or no delay. r

I have this fully set forth how my invention accomplishes the objects for which it is in-.' tended. i

In practice it is shown that with the use of 1 the fibrous packing, as herein described, both the cylinder and the packing wear longer than with the metallic packing usually used, so that, in addition to the accomplishment of the objects as specified, the cost of repairs and the loss by delays incident thereto are reduced to the minimum.

I am fully aware of the fact that fibrous WhatI claim -as new, and desire to secure by Letters Patent, is-

In a rock-drill, the packing P, consisting of a series of rings of fibrous material of a compact natures'uch as leather, rawhide, compressed or vulcanized fiber-each ring being cut substantially as shown, and placed in the groove of the piston-head, as shown, so as to break joints with each other, the groove being filled, yet so as to give the rings a free chance for expansion, as described, in combination with the spring S, the piston D, and cylinder A, all arranged substantially as shown, and for. the purpose herein specified.

LEANDER S. WOODBUBY. Witnesses:

* F. G. GOGGIN,

JAs. M. MERTON. 

